1,2,4-Cyclohexanetricarboxylic acid (CHTA)is a useful organic compound. For example, CHTA can be reacted with one or more aliphatic or aromatic alcohols to prepare the triesters of CHTA. These triesters, particularly those prepared from aliphatic alcohols having 4 to 10 carbon atoms, are useful as synthetic lubricants and as plasticizers. Additionally, CHTA can be reacted with di- or polyfunctional amines such as, 1,6-diaminohexane, to form polymeric amide/imide compounds. When CHTA is reacted with di- or polyamines to form polyamides or polyamide/imides, water is produced during the polymerization reaction. However, by using the anhydride of CHTA, less water is generated during the polymerization reaction allowing for a more efficient, more easily conducted polymerization reaction.
Prior methods for preparing CHTA involved the hydrogenation of the alkali metal or ammonium salt of trimellitic acid, which resulted in the salt of CHTA. In order to form the desired CHTA, the salt required neutralization to the triacid. It would, however, be desirable to produce CHTA directly from trimellitic acid without the use of a salt and the subsequent neutralization step. The present invention provides such an improved method.